1. Field of the Invention
The present invention relates to a reproduction apparatus, and in particular to a VCR (video cassette recorder) for reproducing a digital signal or an analog signal.
2. Description of the Related Art
In recent years, VCRs for reproducing analog signals (such as VHS-VCRs and 8 mm-VCRs) have been made into commercial products. In addition, VCRs for reproducing digital signals have also been developed. Hereinafter, examples of such conventional reproduction apparatuses are described.
In a conventional reproduction apparatus for reproducing analog signals, a frequency multiplexed video signal recorded on a magnetic tape, which includes an FM (frequency modulated) luminance signal and a low-frequency conversion carrier chrominance signal, is reproduced by a magnetic head and then amplified by a video preamplifier. The output of the video preamplifier is separated into the FM luminance signal and the low-frequency conversion carrier chrominance signal components through a high pass filter and a low pass filter, respectively. A reproduced luminance process circuit subjects the FM luminance signal to a limiter process, a dropout compensation, an FM demodulation process, a de-emphasis, a deviation adjustment, a low-frequency filtering, and a noise cancellation process, thereby obtaining a reproduced luminance signal. On the other hand, a reproduced chrominance process circuit subjects the low-frequency conversion carrier chrominance signal to an AGC (automatic gain control) process, a burst de-emphasis, a frequency high-range conversion, and a color killer process, thereby restoring a reproduced carrier chrominance signal. Then, the reproduced luminance signal and the reproduced carrier chrominance signal are added by an adder so as to be output via an output terminal as a reproduced video signal.
On the other hand, an FM audio signal which is recorded on the magnetic tape by a multi-layer recording method is reproduced by a magnetic head, amplified by an audio preamplifier, and separated into a left FM audio signal and a right FM audio signal through band-pass filters. A reproduced FM audio signal process circuit subjects the left and right FM audio signals to a demodulation process, a dropout compensation, a low-frequency filtering, and a noise reduction process, so as to be output via an output terminal as a reproduced audio signal.
Thus, an analog video signal and an analog audio signal can be reproduced.
In a conventional digital signal reproduction apparatus, a signal recorded on a magnetic tape is reproduced by a magnetic head, amplified by a playback amplifier, and then input to a reproduced digital signal process circuit. The reproduced digital signal process circuit subjects the signal to a playback equalization, an AGC process, a channel decoding, a decoding for error correction codes, and an error correction process, thereby outputting a reproduced digital signal via an output terminal. The reproduced digital signal is, for example, an MPEG (Moving Picture Experts Group) signal which is obtained by compressing video image data and audio data in accordance with the MPEG standards. By processing the signal with an MPEG decoder, video and audio output signals can be obtained.
Thus, a digital signal can be reproduced.
In the field of home-use VCRs, the recording/reproduction of analog signals (e.g., by the VHS method) is currently predominant. However, once digital broadcasting or the like is commenced in the future, it will require a VCR which is capable of recording digital signals. Therefore, by accommodating both the above-mentioned analog signal process circuitry and the above-mentioned digital signal process circuitry, it becomes possible for one VCR to reproduce both analog signals and digital signals. Moreover, for simplifying mechanical components and for improved usefulness, the cassette tape for recording digital signals can be adapted to have substantially the same shape and size as those of the cassette tape for recording analog signals, thereby making it possible to reproduce both analog signals and digital signals from one cassette tape.
However, such conventional reproduction apparatuses typically record or reproduce digital signals and analog signals in a mingled manner in the same (or same kind of) cassette tape. As a result, when reproducing a recorded signal, it is impossible to determine whether a digital signal or an analog signal is recorded, so that it cannot be determined whether to operate the digital signal process circuitry or the analog signal process circuitry of the reproduction apparatus.